In a catalytic converter that is provided at an exhaust pipe in order to purify the exhaust generated at an internal combustion engine, there is a structure in which a catalyst carrier (a honeycomb structure) that carries a catalyst is energized and the temperature thereof raised such that a good catalyst effect is obtained even when the engine is cold or the like, as is disclosed in Japanese Patent Application Laid-Open No. 11-257058 (Patent Document 1) for example.
By the way, in the structure disclosed in Patent Document 1, the surfaces of electrode rods that are for energizing the honeycomb structure are subjected to insulating coating so as to prevent deterioration of the insulating ability.
However, when moisture (water vapor) or the like within the exhaust condenses on the surface of an insulating body, the electrodes and the case are short-circuited due to this moisture (liquid). Therefore, there is the concern that the insulating ability between the electrodes will deteriorate and the efficiency of supplying electricity to the catalyst carrier also will deteriorate.